Rare earth metal oxides are known to have good catalytic effectiveness in the direct synthesis of dimethyl carbonate (DMC) from CO2 and methanol. In this work, we screened ceria (CeO2) catalysts by analyzing their capacity for CO2 adsorption. The effects of the crystal surface morphology and oxygen vacancy on the catalytic performance of the ceria catalyst were studied by using density functional theory (DFT). The results show that the (110) surface and higher oxygen vacancy content can better promote the synthesis of DMC and that the rod-shaped CeO2 catalyst has a better catalytic effect. The oxygen vacancy content on the catalyst was improved by freeze-drying and confirmed by thermogravimetric analysis, Raman spectroscopy, and electron paramagnetic resonance. The freeze-dried CeO2 (CeO2-FD) then showed a higher catalytic performance. The conversion rate of methanol and the yield of DMC were 33.95% and 584 mmol g–1cat, respectively, under mild conditions (140 °C and 1 MPa).

Formic acid (FA) is a safe, renewable, and promising hydrogen carrier. A critical challenge is the effective screening of the suitable non-noble-metal-based catalysts for FA dehydrogenation to substitute expensive noble-metal-based ones. Here, a study of all possible catalysts with M–N–C structures (M = 12 metals, −N–C = nitrogen-doped graphene-like surface) for FA dehydrogenation has been conducted using density functional theory (DFT) and followed by experimental analysis. Based on the adsorption energy of critical intermediates, preliminary screening suggests Co as a possible active metal for M–N–C. Experiment and further DFT calculations suggest that atomically dispersed Co sites (Co–N1–C3, Co–N2–C2, and Co–N3–C) are preferable for FA dehydrogenation. The appropriate N contents are critical to the catalytic activity, whose amount can be tuned by choosing different sacrifice templates and the pyrolysis temperature.

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In this work, a novel “foaming” strategy uses sodium bicarbonate (NaHCO3) and ammonium oxalate ((NH4)2C2O4) as the foaming agent, turning biomass-derived carboxymethyl cellulose (CMC) into N-doped porous carbon. Highly active palladium nanoparticles (Pd NPs) immobilized on nitrogen-doped porous carbon (Pd@MC(2)-P) are produced through a phosphate-mediation approach. The phosphoric acid (H3PO4) becomes the key to the synthesis of highly dispersed ultrafine Pd NPs on active Pd-cluster-edge (the edge of the Pd-cluster-100 and Pd-cluster-111 surfaces). The Pd@MC(2)-P exhibits high activity for formic acid (FA) dehydrogenation with an initial TOFg of 971 h–1 at room temperature. The subsequent hydrogenation of phenol using FA as an in situ hydrogen source on Pd@MC(2)-P and the highly efficient hydrogenation of phenol to cyclohexanone reaches more than 90% selectivity and 80% conversion. Density functional theory (DFT) calculations reveal that the reduced H poisoning and more exposed (100) surface over Pd nanoparticles are the keys to the Pd nanoparticles’ high activity.